Method of coating sheets with lubricant for draw dies



E. G. PETERSON 2,809,129

METHOD OF COATING SHEETS WITH LUBRICANT DRAW DIES Filed Oct. 7, 1954 I 3 Sheets-Sheet 1 III.

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.NIEB moi Oct. 8, 1957 METHOD oF coATING SHEETS WITH LUBRICANT FOR DRAW DIES Filed oct. '7, 1954 l E. G. PETERSON 2,809,129

5 Sheets-Sheet 2 3| 32 37 FIG. 3 36 mvENToR:

EDWARD@ PETERSON AT TORNEY Oct 8, 1957 E. G. PETERsoN 2,809,129

METHOD DE coATING sHEETs WITH LUBEICANT EOE DRAW DIES Filed Oct. 7, 1954 5 Sheets-Sheet 3 W I/75Q l I e? lNVE NTOR EDWARD C PETERSON BY:

ATTORNEY United States Patent-IC METHDD OF'LCO'ATING SHEETSWITHLUBRICANT FOR DRAW DIES Edward .'G. Peterson;; .Grand Rapids',.t.Mich.`, assgnor `to Bristol Industrial Equipment Company, Grand Rapids, Mich., a corporation of Michigan Application October 7, 1954, Serial No. 460,9451

1 Cllaim.- (Cl. 117-104)- This invention relates tof the .coating of .metal sheets as a, preparatoryV step Ifor their being formed in a die press. This invention is designedto providebothla methl od anda machineto apply' a..nonoily,l'm tothe, sheet. 'IlielnLacits as a lubricant. to facilitatethe sliding movement of .'the sheetduring lthe .actual formingpprocess betweenthe dies.

WithV theintroduction of modernvsheet metal forming andl drawing processes, particularly .those involving .what is known as. deep dr`awing, it.was yfoundessential.tolubrif catethe material prior toits.introductionbetweenthe dies ,so` that, the... material .'could slip betweenJ the faces of .the 4`dies asfth'e press. closed. Unless .this slippage occurs, the sheetswilltear due .tonon-uniform,stretching of the. material. f

At rst this lubrication .was provided..byconventional hydrocarbon. oils., These oils. providedga satisfactorylu= bric'ant..butit`.,was .exceedingly.difcultito remove the/oil easy to ,remove-, their. initialnapplication-totheJnaterial presents many.diiiicult. problems.. It. is`.the solution 4of theseproblemswhichdsfthe purpose of. this nventiou.

Methodsoapplying `this non-.oily film currently in use,

suc-has sprayingror, rolliug,.have not proved satisfactory.

The charac-ter of vthe nlm produced by thesemethodsyis notentirely satisfactory.f Furtherwthe. methods themselves.-are -diicult to perform... Such methods Anormally apply .thefiilm ,to .one .facero the sheet.. at. a tirne.n e cess r tating a... repetition ofjthe processv to ,fullyp prepare the sheets.,A

Thistinvention.. provides .amethod4 by ,whichthe ,sheet is quicklyand rapidly, coated'- simultaneously en both faces.. The..Lresultiug,v coatingmis substantiallyfuniform and assures proper `fforming `of the. sheetin .the die. VFurther, the coatingis formed with a minimum use. of. .material, thus, eiecting `a .certaineconcmyin the .quanitity of.`lming material demanded ,bytthe machine. The Vmachine accomplishesthese purposes fully. automatically, eliminatinghigh direct labor costs and the c ost of storage and .transportation incident to. a two step application process.4

Other` objects and .purposescf thisV invention will be immediately-seen. by Ithose, acquainted with the prepara tion'-V of. sheetv materials for die presses upon reading the following specication` and the A accompanying drawings.

In. the. drawings:

Fig. .l :is .a somewhatschematic .planview of amachine designed to carry :outmy jinvention.

Fig. 2 ...is a somewhat.,schematicside elevation `View of themachine illustratediu'lig.: l1.

Patented Oct. 8, 1957 Fg..3 is afragmentaryenlarged. plan view ofthelm applying troughs located `in the film application chamber.

Fig. 4 is a fragmentary elevation View taken along the plane IV-IV `of Fig.. 3.

Fig. 5 is an enlarged sectional elevation view taken along the `plane .V-Vof Fig. 3.'

Fig. 6 is a fragmentary centralsectionalelevation View of the lm vapplyingchamber taken along lthe plane VI-VI of Fig. 7.'

Fig. 7 is an:enlarged, sectional, elevation view of one of the conveyor racks for-this machine.

- Fig. 8 isV a fragmentary, enlarged, side elevation view of the conveyor racks for this machine.

Fig. 9 is a plan'view of one .ofthe conveyor racks used inthis machine.

In executing the objects-and` purposes of this invention, there has been-provided a machine consisting basicallyof altunnelV divided into a number of compartments. A conveyor passes-'through this/tunnel for carryingthe materials through all of the steps of the lilm applying process. In the machine, the sheets are washed, drained, rinsed, covered withY lm,drained and dried and delivered vat the other end ready for use-in-v the die presses.

In: applying the-iilm,.the material is cascaded in liquid form onto the sheets from overhead troughs. The troughs are lled'and--the material caused to flow over the tops of the troughs `and thus cascade-in .a thin-sheet onto the sheet material below. As it runs down the sheets, 'the material forms a thin, lubricating film which adheres to the sheets. The excess material is collected at the bottom of the-application-chamberand returned to the vstoragetank for Vthe f1lm-materialwhereinY is recycled until itis used-up in--the'formation' of 'a iilm on-the sheet material.

Referring specifically-to the drawingsghe numeral 10 indicates a tunnelhaving sides V11 and 12, a ltopi-13 (Fig. l) and a bottom i4 (Fig- 6). The top, bottom-and sides areof sheet "metal construction supported by sufficient frame work tomake -them rigid. The frame workv is not shown as itforms no part -of-this invention. Asis indicated in-Fig.` l, the main tunnel Vis divided into ten compartments or operating areas.- The 'direction of movement ofthe belt* is indicated bythe arrow in Figul. As the Vconveyor moves through the-tunnehit passes through ari-entryarea, a rinsearea,` a drain area, a cleaningarea, a second drain area, a second rinse area, a third drain area, a lilm application area, afourthdrain area anda dryingoven. The entry areais vented through a stack 14 50 and the drying oven is vented 'througha stack-i5. The

use ,of these stacks assures the removal of hot `or moisture laden air from inside the tunnel before it can exhaust throughfthe ends ofth'e` tunnel 10 into the Vfaces of the operators as `they are loading-'and unloading the machine.

The various areas and compartment-s have ,a common passageway through them for the hereinafter described conveyor; i6; They are partially seetionedoffgone from lthe other, bysheetmetal baffles 25ct any s' ltable conr struction. Normally these. bales'eXist only'above and below the conveyor for the purpose-of preventing intemixing of the various liquid used such as the cleaner and rinses. Further description of these baiesis notgbelieved'necessary since they are of conventional design.

Materials treated in. Ithe tunnel lt are transported throughthe tunnel by means of a conveyor 1,6. The conveyor 16 passes over a pair of 'pulleys17 and 18'jat opt positeendsof the' tunnel,k The pulley 17 is an idler. The pulley 18 is driven, powering the conveyor. The pulley l'may be driven by any suitable means such as an electrical prime mover.V The power Asourceis not illustrated as it. is wh'olly conventional .and forms no--part ofthis invention. The returnrun 16u' of the conveyor. is spaced just .below-.theor 14 andtherefore is exterior-ofthe 3 operating portion of the tunnel 10. The structure of the conveyor will be described more fully hereinafter.

The rinsing, cleaning and film forming solutions used in the machine are stored to one side of the tunnel in tanks 22 (Fig. l).

Film application mechanism The rinsing and draining operations are carried out by conventional equipment. The rinses are normally applied by nozzles operating from both the top and sides of the rinsing areas to completely spray and clean the sheets. The draining areas are no more than areas of sufficient length to allow sufficient time for the liquids remaining on the sheets to drain off onto the tunnel floor where they are taken away by suitable drain conduits and either returned to the rinsing tanks or discharged entirely.

The particular structure by which the film forming material'itself is applied is quite important to this invention. The film forming material is in liquid form consisting of the lubricating material in an aqueous solution. While this invention is particularly designed for use with current film forming materials which are utilized in an aqueous solution, it is not intended this invention be so limited. It is designed for use with 4any film forming material which will form an adequate film on the sheets when applied by the means incorporated into this machine. The film forming material is raised from the storage tank 22 by means of a pump 19. The pipe 30 (Fig. 4) distributes the material from the pump 19 to the individual troughs 31.

Several troughs 31 are used. These troughs extend laterally across the tunnel just below the tunnels top member 13. The film forming material is delivered to the troughs under very low pressure. Only sufficient pressure is provided to assure an adequate supply to the troughs. The purpose of this will appear more fully hereinafter. The troughs 31 each have a central channel 32. Extending lengthwise of the channel is a distribution conduit 33 having upwardly directed, small, closely spaced, discharge orifices 34 throughout its length (Figs. 3 and 5). The distribution conduits 33 are closed on each end. Thus, all of the film material is discharged into the troughs through the orifices 34. The distribution conduits 33 are each supplied at the center by means of a pipe 3S connected to the conduit 30. The distribution conduits are located deep in the channels 32 whereby discharge of the film materialthrough the orifices 34 will not cause rippling or waving of the top surface of the body of film material filling the channel.

Four troughs are utilized. It will be recognized that while this number has been found sufficient in this machine, under other circumstances a greater or a lesser number of the troughs may be required. Each of the two intermediate troughs are provided with a pair of downwardly and outwardly inclined baffles 36. The baffles are inclined downwardly at approximately 45 and extend outwardly and downwardly from the channel 32 adjacent the bottom of the channel. The trough in Fig. 5 is illustrated with the channel 32 and the bafiies 36 formed with a single piece of material. This is a desirable way of fabricating this particular structure although it may be fabricated from as many different parts as is desirable.

The ends of the channel 32 are closed by 4a terminal plate 37. Each terminal plate is large enough to cover the entire cross-sectional area of the trough 31 including the baffles 36. The terminal plates are secured to the U- shaped member forming the channel 32 and the baffies 36 by suitable means such as welding. Each of the terminal plates 37 is provided with a pair of vertically elongated slots 38. These provide the means for attachment of the troughs to the side members 11 and 12 of the tunnel. Attachment is effected by means of bolts 39 passing through the side members 11 and 12. By means of the slots 38, the troughs may be leveled so that the lm forming material will flow over both edges of the channel 32 in equal quantity.

Below the troughs 31 and below the conveyor 16, the oor 14 of the tunnel slopes downwardly to one side of the tunnel thus causing the excess film material to collect along this side where it is drained through the pipe 50 and returned to the proper storage tank 22 for the film material (Fig. 6).

The end troughs 31a are identical to the troughs 31 except that the outside wall 51 of the channel 32 is made slightly higher than the inside Wall 52. This prevents the filming material from overowing on this side of the trough, confining the discharge of these troughs to the inside edge. Since the walls 51 are raised to prevent the discharge of the film material on the outer side of the troughs, the flanges 36 are omitted along the outer side.

The conveyor The upper run of the conveyor 16 is supported on a track 60 consisting of a pair of L-shaped rails 61 (Figs. 7 and 8). The rails 61 are located one on each side of the tunnel and are secured to the sides 11 and 12 of the tunnel. The conveyor has a pair of side chains 62. Each side chain 62 consists of alternately arranged link pairs 63 and 63a pivotally joined adjacent their ends by pins 64. Rotatably mounted between the links on each of the pins 64 is a carrier wheel 65. The carrier wheels 65 support the chain on the rails 61 of the tracks 60. The inner link of each of the link pairs 63 and 63a is equipped with an inwardly turned, horizontal ear 66. The ears 66 on the inner link of the link pairs 63a is slightly longer than the ear on the inner link of the link pair 63 to account for the differential in location of these links since one pair is mounted exteriorly of the other.

The main body of the conveyor is formed by racks 67 which extend between the conveyor chains 62. The racks each consist of la lateral supporting bar 68 to each end of which is secured an L-shaped anchor bracket 69. The bottom, horizontal leg of each of the anchor brackets 69 rests upon one of the ears 66 and is secured thereto by means of a bolt 70. The racks 67 each have a foot portion formed by a rod 71 extending across the conveyor between the anchor brackets 69, parallel to the supporting bar 68 and spaced a short distance therefrom (Fig. 9). The rod 71 is connected to the supporting bar 68 by short rod segments 72. The ends of the rod 71 are bent back to contact the vertical leg of the brackets 69. The rod segments 72 are secured to both the supporting bar 68 and the rod 71 by welding. In a similar manner, the ends of the rods 71 are secured to the anchor brackets 69 by welding.

The individual sheets 74 (Fig. 8) are supported by vertically extending nesting frames 75 and 75a. Two of the nesting frames 75 and two of the nesting frames 75a are mounted to each support bar 68. The nesting frames 75 and 75a are identical except that the bottom ends of the nesting frames 75 are turned horizontally and extend across the foot of the rack to contact the rod 71 (Fig. 9). Each of the nesting frames is of generally triangular shape having one inclined and one vertical leg. The lower ends of the nesting frames 75 and 75a are firmly secured to the support bar 68 by suitable means such as welding.

The nesting frames 75 and 75a adjacent both their upper and their lower ends have an offset portion 77, offset longitudinally of the conveyor. The inclined legs of the nesting frames 75 and 75a are provided with a corresponding pair of offset portions 78 also offset longitudinally of the conveyor but in the opposite direction from the offset portions 77. The racks 67 are so spaced, 1ongitudinally of the conveyor, that the offset portions 77 of one rack cooperating with the offset portions 78 of the adjacent rack form a slot 79 (Fig. 8) slightly wider than the thickness of the sheet 74 whereby the sheet will seat .between two adjacent racks with its lower end resting on the rod 71 of the racks foot portion. The sheet is held in vertical position by the offset portions. The offset .apriamo since the racks are formed f a thin, rod-like material and above the, wheels 65. -On the return runV the. nesting,

`frames 67; hang'downwardlymflrom,thewheels65 with the conveyor supported from above by thereturn track structure 81 (Fig. i'6).

Operation Before the machine is put into operation, it is essential e that the troughs 31 be properly leveled. These troughs must be level both crosswise and lengthwise of the tunnel so that the liquid will be discharged in an even film over all edges of these troughs. For this purpose, the bolts 39 are loosened to permit the trough to be adjusted in any direction necessary to produce this level condition. It will be seen, when the process carried out in this machine is described, that this leveling of the troughs is essential -to produce a satisfactory film on the sheets.

The sheets are initially placed on the conveyor at the loading end 80. As the racks 67 pivot about the idler pulley 17, they are caused to separate. With the racks 67 separated, the sheets may be easily placed between them. As the conveyor completes its turn about the idler pulley 17, the racks again close up to hold the sheets closely between them. The movement of the conveyor then carries the sheets into the tunnel 10.

In the first rinse chamber, the sheets are thoroughly rinsed to remove any foreign particles such as shavings, chips or other coarse material which may be deposited on their surfaces. As they progress through the tunnel, in the first drain chamber this rinse water is drained oi. They then pass into the cleaner chamber. In the cleaner chamber, the sheets are sprayed with a cleaning solution designed to strip from them any remaining foreign material and any oils or other films which may be on their surfaces. From the cleaner chamber, the sheets pass through a second draining chamber where the cleaner is drained and then into a rinsing chamber where the last traces of cleaner are removed by a thorough flushing.

The sheets then progress into the film application cham ber. In this chamber the troughs 31 and 31a are kept constantly full with lsufficient film material being supplied to the troughs to force the material to run over the edges of the trough. Sufiicient material is supplied to assure a constan-t thin film of material spilling over the tops of the channel 32. This film of material cascades down the sides of the channel and over the baflles 36. The baffles 36 perform the service of joining any divergent stream-s of the material which may form and cause it to cascade onto the sheets 74 in a continuous, unbroken film. Such a cascading process assures a complete coverage of the surfaces of the sheets 74. The rate at which the filming material is supplied to the troughs and the force with which it is discharged through the orifices 34, is such that the filming material in the channel 32 forms a level lake so that it will spill in an even quantity along the entire length of the troughs. It is seen that the troughs must be level, both longitudinally and crosswise to assure the constant discharge of the film in even quantities from all the portions of the troughs.

More material is discharged from the troughs than adheres to the sheets to form the film. This excess material cascades down the sheets and through the conveyor. lSince the conveyor is open at the bottom, the material lrn applying oper .drains free1y-..through the. conveyor onto the` floor 14 of thetunnel vwhereit runs. to one side and is discharged vthrotighthe returnconduitStl. This 'excess film material is Areturned .toQthe` storage tank 22 for thefilm material.

,Theopendesign,ofthe'feet;ofthe racks- 67 permits the material tpfdra-inl awayeasily and quicklyfrom beneath the; sheet s,7.4, thus.l assuring the complete discharge of all .material which; doesv not adhere to the surfaces of the sheets.

The high outer sides 51 of the troughs 31a confines the cascading action to the central portion ofthe lrn appli- Galion chan-iben. 11.1115, the filmwill not be accidentally caused. to; splash, into 'theadjacent rinsing and draining chambers,

Afterthe sheetshave been subjected -to the cascading 'onfthev mov-e through 'fi-draining fea Whereithelast n `the excessfilm material is drained off. VAs'in Ythe ap'p'lication chamber, this drained off material is collected on the floor of the 4tunnel and returned to the film storage tank. The conveyor then passes through a drying oven where the sheets are heated to sufficient temperature to set the lming material and dry off the remaining moisture. The open construction of the racks 67 assumes even and adequate heating of all parts of the sheets 74. The open foot portion of the racks assures circulation of lthe heated air about the bottom ofthe sheets.

Heating may be effected in the drying oven by any suitable means such as by supplying the oven with adequate quantities of hot, dry air. This is a preferable arrangement lbecause the heat source may be provided separate and apart from the tunnel and may be closely regulated to the requirements of the material being processed. However, it is entirely possible to substitute infrared heating units within the drying oven.

As the conveyor 16 emerges from the drying oven, the stack 15 removes the hot air so that it does not discharge into the operators face. The sheets, as they exit from the tunnel, are completely coated and dried ready for use in the die press. The conveyor then passes over the driven pulley 18 at its discharge end 82. As the conveyor turns about the pulley, the racks 67 are caused to separate, thus permitting the sheets 74 to be removed quickly and easily by the operator. The conveyor then returned to the loading end of the conveyor beneath the floor of the tunnel in inverted position.

The open design of the racks assures a complete coverage of the sheets and at the same time assures complete drainage of the sheets so there will be no Wet points on the sheets after they have passed through the drying oven. Further, the design of the rack 67 is such that the conveyor is capable of carrying a large quantity of sheets since the sheets are spaced only about three inches apart along the conveyor. Thus, the machine, although necessary moving slowly through the tunnel, is capable of processing as a continuous operation a large quantity of material in a short period of time.

It will be seen that the operation, as carried out in this machine, is entirely automatic, the only operator necessary being a loader and unloader. It will be recognized that even these operators may be eliminated by the use, in association with this machine, of automatic mechanical loading and unloading equipment.

The coating of the sheets with a cascading action of a continuous film of the film forming material assures complete coverage. Furthermore, it makes it possible to coat the sheets simultaneously on both faces, thus doing the entire job in a single passage through the machine. The construction of the machine is such that practically none of the film forming material is Wasted since that which does not adhere to the sheets is collected and cycled for reuse. The use of excess quantities of the film made possible by cascading action assures complete coverage. As a result, there are no uncoated spots to cause difficulty when the sheets are placed in the die presses. The operation is carried out swiftly and completely, permitting large quantities of sheet material to be prepared rapidly and completely with practically no opportunity for defective coating of the sheets.

While I have described a preferred embodiment of my machine, it will be recognized that various modifications of this invention may be made. Such modifications are to be considered as included in the hereinafter appended claims unless these claims by their language expressly state otherwise.

I claim:

In a method for coating sheet material prior to forming in a die press, the steps which include: cleaning said sheet material; holding each individual sheet of said sheet material in vertical and spaced apart relationship; cascading excess quantities of a liquid lm forming lubricant in a plurality of thin, substantially unbroken sheets over all surfaces of said sheet material simultaneously; whereby a film of said film forming lubricant adheres to `the surfaces of said sheets; draining the non-adhering portion of said film forming lubricant from said sheets; drying said sheets.

' References Cited in the le of this patent UNITED STATES PATENTS 

